Amount Of Extraction Solvent Research Articles

Optimizing Analysis Methods: Rapid and Accurate Determination of Cuaminosulfate Residues with LC-MS/MS Based on Box-Behnken Design Study.

In view of the defects in the previous detection of cuaminosulfate, which only focused on the analysis of copper ions, there is currently no analysis method available to determine the actual state of cuaminosulfate as chelated or bound. In order to investigate the dissipation and terminal residues in soil and watermelon of cuaminosulfate for food safety and environmental risk, a highly effective technique was developed to detect cuaminosulfate residues in watermelon and soil, and field experiments were conducted in China. After single-factor experiments, residual cuaminosulfate in samples was extracted by pure water, purified using a liquid-liquid approach combined with a dispersive solid-phase extraction, and detected by liquid chromatography tandem mass spectrometry (LC-MS/MS). The Box-Behnken design (BBD) study was used to find the optimal solutions for the time of liquid-liquid purification, the amount of extraction solvent, and the amounts of cleanup sorbents for the analytical method. The average recovery of the method was in the range of 80.0% to 101.1%, the average relative standard deviation (RSD) was 5.3-9.9%, and the detection limit was lower than 0.05 mg/kg. The BBD study not only improved the extraction rate of the method, but also saved time and was operated easily. The final residues of cuaminosulfate in watermelon at different sampling intervals were all lower than 0.05 mg/kg under field conditions. The cuaminosulfate in soils dissipated following exponential kinetics, with half-life values in the range of 9.39 to 12.58 days, which varied by different locations. Based on the validated method, food safety residues and soil residues can be determined rapidly and accurately.

An environmentally friendly microextraction method for the determination of cadmium in water samples

An environmentally friendly switchable solvent based microextraction method was developed for cadmium ions prior to determination by FAAS. N, N-dimethyl-n-octylamin and 1-(2-Pyridylazo)-2-naphthol were used as switchable solvent and ligands, respectively. Important method parameters such as pH, amount of extraction solvent and ligand, volume of sample and NaOH and foreign ions effects have been optimized. Limits of detection and quantification, preconcentration factor were determined as 0.063 mg L-1, 0.21 mg L-1 and 60, respectively. The validation study of the developed method was carried out by spiking a fixed amount of cadmium to the water samples and determining the recovery. The method was used to determine the cadmium ions content of various environmental water samples.

Microextraction of Tigecycline Using Deep Eutectic Solvents and Its Determination in Milk by LC-MS/MS Method.

The occurrence of tigecycline (TGC), a new first glycylcycline antibiotic residues in food products harmfully influences potential human consumers health. Therefore, analysts are forced to develop new microextraction methods connected with modern extractants for effective isolation of this compound. For this purpose, deep eutectic solvents (DES) as the extraction media were used. Liquid-liquid microextraction (LLME) of tigecycline from milk samples with application of the hydrophobic deep eutectic solvents: decanoic acid:thymol (1:1), thymol:camphor (2:1), dodecanoic acid:menthol (2:1), and dodecanoic acid:dodecanol (1:1) was developed. The studied samples were subjected to a deproteinization process using trichloroacetic acid solution and acetonitrile. The optimal microextraction parameters, molar ratio of DES components, amount of extraction solvents, pH of milk sample, shaking, and centrifugation time, were chosen. Tigecycline in the obtained microextracts of deep eutectic solvents was analyzed using a liquid chromatographic technique connected with a tandem mass spectrometry (LC-MS/MS) system. The limits of detection and quantification values for TGC determination followed by DES-LLME-LC-MS/MS method were in the 1.8 × 10-11 mol L-1 (0.01 μg kg-1) to 4.0 × 10-9 mol L-1 (2.28 μg kg-1) and 5.5 × 10-11 mol L-1 (0.03 μg kg-1) to 1.2 × 10-8 mol L-1 (6.84 μg kg-1) ranges, respectively. The RSD values of precision were in the range 1.4-7.8% (intraday) and 5.4-11.7% (interday). The developed procedures were used for the determination of tigecycline in different bovine milk samples.

Simultaneous determination of ten neonicotinoid insecticides and a metabolite in human whole blood by QuEChERS coupled with UPLC-Q Exactive orbitrap high-resolution mass spectrometry

Since neonicotinoid insecticides are now the most extensively used insecticides worldwide, there are increasing cases of neonicotinoid poisoning. A rapid and sensitive method was developed for the determination of ten neonicotinoid insecticides and a metabolite 6-chloronicotinic acid in human whole blood. The types and amounts of extraction solvent, salting-out agent, and adsorbent in the QuEChERS method were optimized by comparing the absolute recoveries of 11 analytes. The separation was performed on an Agilent EC18 column with the gradient elution with 0.1% formic acid in water and acetonitrile as the mobile phase. The quantification was achieved by Q Exactive orbitrap high-resolution mass spectrometry under parallel reaction monitoring scan mode. The 11 analytes showed good linearity with R2 ≥ 0.9950, LODs ranging from 0.01 μg/L to 0.30 μg/L, and LOQs from 0.05 μg/L to 1.00 μg/L. The recoveries ranged from 78.3% to 119.9% at low, medium, and high spiked concentrations of blank blood, with matrix effects ranging from 80.9% to 117.8%, inter-day RSDs from 0.7% to 6.7%, and intra-day RSDs from 2.7% to 9.8%. The method was furthermore applied to a real case of neonicotinoid insecticide poisoning to demonstrate its feasibility. The proposed method is suitable for the rapid screening of neonicotinoid insecticides in poisoned human blood in the field of forensic science, as well as monitoring of neonicotinoid insecticide residues in humans in the field of environmental safety, compensating for a lack of studies on neonicotinoid insecticide determination in biological samples.

Dispersive liquid-liquid microextraction based on a supramolecular solvent followed by high-performance liquid chromatographic analysis of lignans in Forsythiae Fructus.

A supramolecular solvent-based dispersive liquid-liquid microextraction was proposed for the extraction and determination of lignans in Forsythiae Fructus combined with high-performance liquid chromatography. The supramolecular solvent, consisting of tetrabutylammonium bromide and n-hexanol, was mixed with the sample solution to extract the analytes by a vortex. After accomplishing the extraction, the extraction phase was separated by centrifugation and collected for high-performance liquid chromatography analysis. In this work, the important extraction variables such as the type and amount of extraction solvent, pH and salt amount in the sample phase, and extraction time were optimized. The synthesis of supramolecular solvent was studied and its microstructure was characterized by transmission electron microscopy. Under the optimal conditions, the analytes' enrichment factors were between 6 and 170 for the proposed procedure. Satisfactory linear ranges (r ≥ 0.99), detection limits (0.025-0.4ng/ml), precisions (<9.2%), and accuracies (recoveries: 96.5%-104.8%) were obtained. The method has been successfully applied to the preconcentration of lignans in Forsythiae Fructus with simple and rapid operation, low cost, and environmental friendliness.

Microextraction of ampicillin from bovine milk using ionic liquids and deep eutectic solvents prior to its chromatographic determination with ultraviolet and tandem mass spectrometry detection

Liquid-liquid microextraction procedures using ionic liquid (IL) and deep eutectic solvent (DES) as the new extractants for isolation of β-lactam antibiotic ampicillin (AMP) from milk samples were developed. In this purpose IL: 1-butyl-3-methylimidazolium hexafluorophosphate and DES: choline chloride-thymol (1:2) were used as the extraction medium. These green solvents are characterized by favorable solvating properties for a range of compounds. Ionic liquid was used as extractant in dispersive liquid-liquid microextraction (DLLME) connected with acetonitrile as disperser solvent while deep eutectic solvent was applied for liquid-liquid microextraction (LLME). The isolation parameters of ampicillin, namely, amount of extraction solvents, pH of milk sample, shaking and centrifugation time were optimized. The extracts were analyzed followed by liquid chromatographic method with ultraviolet (HPLC-UV) and tandem mass spectrometry (LC-MS/MS) system for DLLME and LLME isolation procedures, respectively. The calibration curves were linear in the analyte concentration range of 1 . 10−7 mol L−1 (36.1 µg kg−1) – 1 . 10−4 mol L−1 (36127.0 µg kg−1) for IL-DLLME-HPLC-UV technique and 1 . 10−8 mol L−1 (3.6 µg kg−1) – 1 . 10−4 mol L−1 (36127.0 µg kg−1) for DES-LLME-LC-MS/MS method. The elaborated procedures were applied for the determination of ampicillin in the different milk samples.

Ultrasonic Microwave-Assisted Micelle Combined with Fungal Pretreatment of Eucommia ulmoides Leaves Significantly Improved the Extraction Efficiency of Total Flavonoids and Gutta-Percha.

A biological pretreatment of Eucommia ulmoides leaf biomass was carried out. Above all, the total flavonoids were isolated from Eucommia ulmoides leaves by the treatment of alkaline solution of sodium dodecyl benzene sulfonate combined with ultrasonic microwave. The extraction parameters were optimized by central composite design (CCD) software and were displayed as follows: surfactant concentration of 1.5%, microwave power of 700 W, extraction time of 30 min, and liquid–solid ratio of 50 mL/g. The actual yield of total flavonoids was 1.45%. The results of Sudan III color development showed that the cuticle of Eucommia ulmoides leaves was completely removed after dilute alkali pretreatment. Then, Eucommia ulmoides leaves were fermented by Trichoderma viride to remove the holocellulose and obtain gutta-percha. The content of cellulose and hemicellulose in Eucommia ulmoides leaves obviously decreased after Trichoderma viride fermentation. The optimum parameters were listed as follows: solid–liquid ratio of 0.06 g/mL, four extraction times, extraction time of 89.72 min, and extraction temperature of 85 °C. The actual yield of gutta-percha was 4.38%. The amount of extraction solvent per unit weight of gutta-percha from untreated Eucommia ulmoides leaves was 2.91 mL/mg, while that from leaves treated by Trichoderma viride was only 0.96 mL/mg. The amount of extraction solvent was grossly reduced, which is beneficial in terms of environmental protection. The characterizations of gutta-percha were verified by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and proton nuclear magnetic resonance (1H NMR). This study laid a certain theoretical and experimental basis for the multi-stage extraction of Eucommia ulmoides leaves and the utilization of Eucommia ulmoides resources.

5'-Ribonucleotides production using 5'-phosphodiesterase from spent malt roots

Abstract 5'-ribonucleotides are high value-added molecules widely used in the food and pharmaceutical industries because of their bioactive properties. The present work aims to produce a composition of 5’-ribonucleotides using spent brewer’s yeast as cheap source of RNA, and barley malt rootlets as cheap source of 5'-phosphodiesterase (5'-PDE). This is a very promising and innovative strategy because both spent yeast and malt rootles are residues of the brewing process and are closely linked in a cycle that until now is not yet commercially exploited due to lack of studies. Our results showed that extraction of 5’-PDE was mainly influenced by the fineness of the rootlets and amount of extraction solvent (water). The main molecules formed during RNA hydrolysis were 5’-ribonucleotides, which represented 85.86% of the total hydrolyzed molecules. Finally, the results of the proposed approach can generate a new perspective for the brewing industry regarding the management of its wastes, generating from them products of high added value and with a wide range of applications.

Kinetic study on polyphenol and antioxidant activity from karonda fruit (Carissa carandas) extraction via microwave

Karonda fruit (Carissa carandas L.) is a tropical fruit rich in biological value due to its high total polyphenol content with potential antioxidant activity. In this study, the kinetics of total polyphenol and antioxidant activity extraction from the karonda fruit by microwave-assisted extraction technique was performed. Microwave power varies from 150, 300, and 450 (W); the ratio of material/solvent varies from 1:20, 1:40, and 1:60 (g/mL). The results show that changes in total polyphenol concentration and antioxidant activity during extraction can be predicted by a second-order kinetic model. Increasing the microwave power or amount of extraction solvent had the effect of increasing the extraction efficiency and extraction rate constant. However, the saturation concentration and the initial extraction rate increased when MW power increased or the amount of extraction decreased. In further study, the highest quality of extract, collected at the optimized conditions of microwave-assisted extraction, could be used to develop new food products for the health benefits of customers.

Towards green analysis of curcumin from tea, honey and spices: Extraction by deep eutectic solvent assisted emulsification liquid-liquid microextraction method based on response surface design

ABSTRACT A fast, cheap and green analytical method was developed for the determination and extraction of curcumin in tea, honey, and spices using deep eutectic solvent-assisted emulsification liquid–liquid micro-extraction (DES-ELLME) coupled to UV-VIS spectrophotometry. Quantitative extraction of curcumin from the sample was obtained by the DES, which was prepared by mixing choline chloride and maltose in a 1:3 molar ratio. Response surface design was used for the optimisation of significant experimental parameters including sample pH, amount of extraction solvent, amount of emulsifier solvent and vortex time. The optimum conditions obtained were pH 4.25, 762.5 μL of DES, 107.5 mL of tetrahydrofuran and 3.4 min vortex time, while keeping centrifugation speed fixed at 4000 rpm, 5 min. Under the extraction conditions obtained, analytical features such as calibration equation, limit of detection, enrichment factor, and linearity were Abs = 6.5 × 10−4 [Curcumin, ng mL−1]-1.2 × 10−5, 0.1 ng mL−1, 114 and 0.4–120 ng mL−1, respectively. Moreover, the repeatability and reproducibility of the DES-ELLME method, expressed as relative standard deviation (RSDs%), varied in the ranges of 1.4–3.0% and 2.0–4.3%, respectively. Finally, the proposed method was successfully applied to the extraction and determination of curcumin from prepared samples. The relative mean recovery ranged from 92.3% to 104.4%.

Deep eutectic-based vortex-assisted/ultrasound-assisted liquid-phase microextractions of chromium species

In the present work, vortex-assisted liquid-phase microextraction (VA-LPME) and ultrasound-assisted liquid-phase microextraction (UA-LPME) techniques were used for the speciation of chromium (Cr3+/Cr6+) followed by their determination using flame atomic absorption spectrometry. 1-(2-Pyridylazo)-2-naphthol (PAN) was used as a chelating agent to form a hydrophobic complex with Cr3+; then, it was extracted by choline chloride–phenol mixture, as an extraction solvent. A solution of 1.0 mol L−1 ascorbic acid was used as a reducing agent to convert Cr6+ to Cr3+ (total chromium), and the concentration of Cr6+ was determined from the subtraction of Cr3+ form total chromium. The efficiency of two microextraction techniques was compared in terms of type and amount of extraction solvent, type and volume of extraction solvent, pH of solution, volume of tetrahydrofuran (THF), and extraction time. Based on the obtained results, the extraction recoveries of VA-LPME and UA-LPME techniques are 52% and 60%, respectively. Therefore, UA-LPME is superior technique than VA-LPME. By optimizing different parameters affecting the recovery percentage (RP) of Cr3+, the calibration curve was depicted in the concentration range of 1.5–375.0 ng mL−1 Cr3+ with a correlation coefficient of 0.9937. The limit of detection was 0.4 ng mL−1, and the relative standard deviation (RSD%) for seven replicate analyses of 50.0 µg L−1 of Cr3+ was 3.6%. Finally, the UA-LPME method was successfully applied for the determination of Cr species in different food and water samples.

Simultaneous determination of six alkaloids in tobacco and tobacco products by direct analysis of real-time triple quadrupole mass spectrometry with a modified pretreatment method.

In order to determine six alkaloids (mass fraction) of nicotine, nornicotine, myosmine, anatabine, anabasine, and nicotyrine in tobacco and tobacco products quickly, accurately, and simultaneously, a novel method based on direct analysis of real-time model in situ ionization technique combined tandem mass spectrometry with a modified sample pretreatment was established, in which experimental parameters such as the type and amount of extraction solvent and injection rate were optimized, respectively. The samples of five commercial cigarettes and five kinds of tobacco leaves were analyzed by the established method, and the determined values were compared with those obtained using a gas chromatography with mass spectrometry method: (1) Under optimized conditions (30mL ultrapure water as extraction solvent and with extraction rate of 0.6mm/s), analysis could be completed within 10min. (2) The linear range of the method was 0.002-2000μg/g with , the recovery ranged from 86.8 to 105.6%, and the limit of detection and the limit of quantification were 0.004-0.835μg/g and 0.013-2.787μg/g, respectively. (3) The relative standard deviation between direct analysis of real-time method and the gas chromatography with mass spectrometry method was 0.34-8.83%. The established method is rapid, reliable, and suitable for the ultrafast determination of six alkaloids in tobacco and tobacco products.

Simple and Green Heat-Induced Deep Eutectic Solvent Microextraction for Determination of Lead and Cadmium in Vegetable Samples by Flame Atomic Absorption Spectrometry: a Multivariate Study.

In this study, a simple, green, and cheap analytical procedure based on heat-induced deep eutectic solvent microextraction (HI-DES-ME) coupled with flame atomic absorption spectrometer (FAAS) was developed for the determination of Pb(II) and Cd(II) in vegetables. After the preliminary experiment, response surface methodology (RMS) based on central composite design (CCD) was used for the optimization of critical factors such as pH of sample solution, amount of extraction solvent, temperature, and amount of ligand. Microwave step was applied for the digestion of vegetable samples. Under optimum conditions obtained by the CCD, calibration graphs for Pb(II) and Cd(II) were linear in the concentration range of 0.5-250 and 1.0-300ngmL-1, respectively. Limits of detection (LODs) and sensitivity enhancement factor (SIFs) were found in the range of 0.17-0.35ngmL-1 and 93-67ngmL-1, respectively. Relative standard deviations (N = 10, RSDs%) for Pb(II) (10ngmL-1) and Cd(II) (50ngmL-1) were 3.7% and 2.3%, respectively. In order to validate the proposed method, certified reference material (CRM) and spiked samples were used. Experimental results showed that there was no significant difference between the obtained and certified values. Then, the proposed method was successfully applied for the preconcentration and determination of Pb(II) and Cd(II) in different vegetables.

Undecanol-ethanol-water ternary system based microextraction for the detection of cadmium

An eco-friendly, simple, and sensitive solidification of floating organic drop based dispersive liquid?liquid microextraction (SFODME) procedure was introduced for the separation and preconcentration of cadmium. After 2-(5-bromo- -2-pyridylazo)-5-(diethylamino)phenol (5-Br-PADAP) was complexed with cadmium ions in sample, the undecanol?ethanol?water ternary system was used as an organic solvent for extraction. The main factors relevant to the microextraction efficiency such as pH, concentration of 5-Br-PADAP, amount of extraction solvent were optimized. The detection limit is 0.01 ?g L-1 along with preconcentration factor 266. The recovery of the analyte was between 98 % and 103 %, with relative standard deviation below 6 %. The developed procedure was successfully tested on the analysis of water, hair dye, and food samples.

Determination of trace amount of cadmium using dispersive liquid-liquid microextraction-slotted quartz tube-flame atomic absorption spectrometry

This study was performed to develop a sensitive analytical method for the determination of cadmium by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) after dispersive liquid-liquid microextraction (DLLME). The parameters affecting the cadmium complex formation and its extraction output were optimized to obtain high extraction efficiency. These included the pH and amount of the buffer solution, and the concentration of the ligand. The DLLME method was comprehensively optimized based on the type and amount of extraction solvent, dispersive solvent and salt. The type and period of mixing needed for a more effective extraction was also investigated. In order to further improve the sensitivity for the determination of cadmium, the flame atomic absorption spectrometry was fitted with a slotted quartz tube to increase the residence time of cadmium atoms in the pathway of incident light from a hollow cathode lamp. The limits of detection and quantitation (LOD and LOQ) for the FAAS were found to be 42 and 140μgL−1, respectively. Under the optimum conditions, LOD and LOQ of the FAAS after DLLME were calculated as 1.3 and 4.4μgL−1, respectively. Combining both optimized parameters of the DLLME and SQT-FAAS gave 0.5 and 1.5μgL−1 as LOD and LOQ, respectively. Accuracy of the method was also checked using a wastewater certified reference material (EU-L-2), and the result was in good agreement with the certified value.

Lead preconcentration as rac-(E,E)-N,N′-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine complexes from water and tobacco samples by dispersive liquid-liquid microextraction

A dispersive liquid-liquid microextraction (DLLME) procedure for determination of Pb(II) in water and tobacco samples has been developed using rac-(E,E)-N,N′-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine as a chelating agent. Factors influencing the efficiency of DLLME have been optimised, including metal solution pH, type and amount of dispersing solvent, type and amount of extraction solvent, amount of chelating agent and sample volume. The optimized conditions for maximum recovery were as follows: sample pH 6; dispersing solvent, 500 μL of ethanol; extraction solvent, 150 μL of chloroform; chelating agent, 150 μL of 0.01% rac-(E,E)-N,N′-bis(2-chlorobenzylidene)cyclohexane-1,2-diamine; and sample volume, 15 mL. The method was validated using the certified reference material SPS-WW2 waste water. The method offered a limit of detection (LOD) of 2.6 μg/L, a limit of quantification (LOQ) of 8.5 μg/L, and a relative standard deviation (RSD) of 5.2%.

Utilization of a novel microwave-assisted homogeneous ionic liquid microextraction method for the determination of Sudan dyes in red wines

A novel microwave-assisted homogeneous ionic liquid microextraction (MA-HILME) method was first developed for the extraction of Sudan dyes in red wines followed by detection using high-performance liquid chromatography. 1-dodecyl-3-methylimidazolium bromide ([C12MIM]Br) was used as extractant in a microwave-assisted extraction (MAE) procedure, and then transferred into hydrophobic solid-state ionic liquid after adding ammonium hexafluorophosphate ([NH4][PF6]). The separation between liquid state sample and solid state extractant can be realized easily. Several experimental parameters, including type and amount of extraction solvent, microwave power and irradiation time, amount of ion-exchange reagent ([NH4][PF6]), pH of sample solution, and ionic strength, were evaluated. Under the optimum experimental conditions, the linearity for the determining of the analytes was in the range of 0.5–100μgL−1, with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for Sudan I, Sudan II, Sudan III, and Sudan IV were 0.19, 0.18, 0.24, and 0.16μgL−1, respectively. When the present method was applied to the determination of Sudan dyes in red wines, satisfactory recoveries were obtained in the range of 78.5–106.8%, and relative standard deviations were lower than 9.7%.

Simultaneous Preconcentration and Analysis of Anthraquinones Based on Ultrasound Emulsification Ionic Liquid Microextraction

An ultrasensitive method of ultrasound emulsification ionic liquid microextraction (UEILME) coupled with high-performance liquid chromatography (HPLC) has been developed and introduced for the preconcentration and analysis of anthraquinone additives in cosmetic samples and five anthraquinone compounds (aloe-emodin, rhein, emodin, chrysophanol and physcion) in traditional Chinese medicines. Several parameters affecting the extraction efficiency were investigated and optimized, such as the type and amount of extraction solvent, sample pH, ultrasound time and temperature, centrifugation speed and time and ionic strength. The most favorable results were obtained using 60 mg of 1-hexyl-3-methylimidazolium hexafluorophosphate as extraction solvent. The anthraquinones were extracted from the aqueous solution (pH 2.0) by ultrasound at 40°C for 7 min and centrifuged at 2,500 rpm for 6 min. Under optimal conditions, acceptable linearity of the five anthraquinone compounds was obtained with correlation coefficients > 0.99. The limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.01 to 0.09 µg/L and 0.05 to 0.25 µg/L, respectively. The relative standard deviations (n = 3) were less than 9.8%. Moreover, the enrichment factors ranged from 80 to 197-fold. Compared with conventional dispersive liquid-liquid microextraction, the UEILME technique exhibited lower LODs and LOQs. The results demonstrated that the UEILME coupled with HPLC is a simple, environmentally friendly, sensitive and efficient method for the extraction, concentration and analysis of anthraquinone compounds.

Ultrasonic assisted extraction combined with titanium-plate based solid phase extraction for the analysis of PAHs in soil samples by HPLC-FLD

In this work, ultrasonic assisted extraction combined with solid phase extraction (SPE) was applied in the analysis of polycyclic aromatic hydrocarbons (PAHs) in environment samples. A titania nanotubes/titanium plate was modified with n-octadecanethiol monolayer-protected Ag nanoparticles, and developed as the adsorbent in SPE of PAHs. Six different PAHs in soil samples were analyzed with high performance liquid chromatography-fluorescence detection. The experiment conditions including the deposition time of Ag nanoparticles, extraction solvent properties, the amount of extraction solvent, the amount of organic modifier, extraction time, and desorption solvent properties were optimized. Under the optimized conditions, good linearity and low limits of detection of 0.0015–0.4ngg−1 were obtained. The analysis of PAHs in real soil samples gave satisfactory recoveries ranging from 70.32% to 115.51% with 3.14%–13.56% intra-day relative standard deviations (RSD) and 4.92%–14.87% inter-day RSD.

Study on the Extraction and Purification of Microcystins (MC-LR)

The MC-LR from the the blue-green algae of Taihu Lake was extracted, at the same time, a set of microcystins extraction method with methanol as extraction solvent and purification method with C18-SPE as purification workstations were established. The extraction solvent concentration, extraction time, extraction solvent amount, leacheate concentration and eluent concentration were used to research the extraction efficiency of MC-LR. Finally, 80% methanol was used to wash microcytins to make MC-LR high purity and the purity was over 85%. This research presented a method of low cost and high efficiency. It provided the foundation for the further research of microcytins.